Q&A - PSLE Math

[Muku]

MathIzzzFun:

Andrew Lee:

[quote=\"WWong\"]Hi tianzhu,


Thank you very much for your kind guidance.

WWong

Hello, can help me solve this headpain sch question ?
http://i53.tinypic.com/2s6sjmp.jpg\">

Hi

You can use MD as done for a similar question - http://www.flickr.com/photos/62167097@N02/5679183503/in/photostream

or we can also use \"units\" & \"parts\" ie simultaneous equations/algebra...

X = 6 units
Y = 9 parts
Shaded = 1/2 X + 1/3 Y = 3 units + 3 parts

X+Y = 3/4 C, C = 4/3 (X+Y) = 8 units + 12 parts ...(eq 1)

3/10 C is shaded, so 3 units + 3 parts = 3/10 C
C = 10 units + 10 parts = 8 units + 12 parts (from eq 1)
so 1 unit = 1 part

X : Y = 6 units : 9 parts = 6 units : 9 units = 2 : 3

cheers.[/quote]Hi hi,

For your second equation, \"3/10 C is shaded, so 3 units + 3 parts = 3/10 C\", it doesn't look correct to me. Looks more like 3 parts = 3/10C. The 3 units is not part of circle Z.

I can't seem to get a logical answer. Can help reconfirm if there's anything wrong with this sum?

Thanks!

[ozora]

Need help.Jim has 3 cubicle tanks of different sizes. The length of Tank A is twice the length of Tank B and the length of Tank B is twice the length of Tank C. Jim filled 20% of Tank A,35%of Tank B and 40% of Tank C with water at first. He then poured all the water from Tank B and Tank C into Tank A. What percentage of Tank A is filled with water now? Can you please solve this question?

[Andrew Lee]

MathIzzzFun:

Andrew Lee:

[quote=\"WWong\"]Hi tianzhu,


Thank you very much for your kind guidance.

WWong

Hello, can help me solve this headpain sch question ?
http://i53.tinypic.com/2s6sjmp.jpg\">

Hi

You can use MD as done for a similar question - http://www.flickr.com/photos/62167097@N02/5679183503/in/photostream

or we can also use \"units\" & \"parts\" ie simultaneous equations/algebra...

X = 6 units
Y = 9 parts
Shaded = 1/2 X + 1/3 Y = 3 units + 3 parts

X+Y = 3/4 C, C = 4/3 (X+Y) = 8 units + 12 parts ...(eq 1)

3/10 C is shaded, so 3 units + 3 parts = 3/10 C
C = 10 units + 10 parts = 8 units + 12 parts (from eq 1)
so 1 unit = 1 part

X : Y = 6 units : 9 parts = 6 units : 9 units = 2 : 3

cheers.[/quote]Thank you so much :imcool:

[Andrew Lee]

MathIzzzFun:

Andrew Lee:

[quote=\"WWong\"]Hi tianzhu,


Thank you very much for your kind guidance.

WWong

Morning,
Janelle went to a florist to buy some flowers. She spent 1/6 of her money on q bouquet of roses and $154 on a bouquet of lilies. She spent 1/9 of her remaining amount on a bouquet of carnation flowers. If the amount of money left was $240 more than 1/4 of the amount she had at first, how much had she left? :?

Hi

http://i56.tinypic.com/i69p3n.jpg\">

cheers.[/quote]Hello, here got two questions need help
Q1. Mr Singh was travelling at a constant speed from Town A to Town B. he passed a car travelling at a constant speed of 90km/h in the opposite direction. 1hr 30min later,Mr Singh reached Town B but the car still 25km away from Town A. If Mr Singh took 4hrs to complete the whole jorney. What is the distance between the 2 towns?

Q2. At first, Din had only $5 notes and Bella had only $2 notes. The number of notes Bella had is 80% of Din's notes. When Bella gives Din $100.00, the number of notes Din has now is 70% more than Bella. How many notes did Din have at first? :imdrowning:

[P6ians]

Hi

Q.1:
1h 30min--1.5h
1.5hx90=135km
135+25=160km
160km/(4-1.5)=64km/h
64x4h=256km(answer)
Q.2:(in this question,total remains the same)
Before. After
D:B. D:B
4:5.|9u 10:17|27u
12:15|27u
12u-10u=2u
2u----(100/2)
15u---$375(answer)

[Andrew Lee]

P6ians:

Hi

Q.1:
1h 30min--1.5h
1.5hx90=135km
135+25=160km
160km/(4-1.5)=64km/h
64x4h=256km(answer)
Q.2:(in this question,total remains the same)
Before. After
D:B. D:B
4:5.|9u 10:17|27u
12:15|27u
12u-10u=2u
2u----(100/2)
15u---$375(answer)

Thank you so much :rahrah:

[Yvonne Tan]

Nanyang prelim 2011

Ali and Ben started jogging from Park X to Park Y at the same time. Ali jogged at an average speed of 7.5km/h while Ben jogged at an average speed of 4.5km/h. After jogging for 1.2h, Ali decided to turn back and jog towards Ben. Ali met Ben at point Z which was halfway btw Park X and Park Y. Ali and Ben then continued their jog together towards Park Y at an average speed of 4.5km/ h. What was the distance between park X and park Y.

Age problem

When Kok’s age was twice as Bala’s age, Mike’s age was 30. When Mike’s age was twice Kok’s age, Bala’s age was 21. Given that Mike was the oldest among the three persons, find Bala’s age when Mike was 62 years old. Thanks.

Thanks.

[Andrew Lee]

P6ians:

Hi

Q.1:
1h 30min--1.5h
1.5hx90=135km
135+25=160km
160km/(4-1.5)=64km/h
64x4h=256km(answer)
Q.2:(in this question,total remains the same)
Before. After
D:B. D:B
4:5.|9u 10:17|27u
12:15|27u
12u-10u=2u
2u----(100/2)
15u---$375(answer)

Sorry, for Q2, the question asking how many notes? not how much... :oops:

[MathIzzzFun]

Muku:

MathIzzzFun:

[quote=\"Andrew Lee\"]

Hello, can help me solve this headpain sch question ?
http://i53.tinypic.com/2s6sjmp.jpg\">

Hi

You can use MD as done for a similar question - http://www.flickr.com/photos/62167097@N02/5679183503/in/photostream

or we can also use \"units\" & \"parts\" ie simultaneous equations/algebra...

X = 6 units
Y = 9 parts
Shaded = 1/2 X + 1/3 Y = 3 units + 3 parts

X+Y = 3/4 C, C = 4/3 (X+Y) = 8 units + 12 parts ...(eq 1)

3/10 C is shaded, so 3 units + 3 parts = 3/10 C
C = 10 units + 10 parts = 8 units + 12 parts (from eq 1)
so 1 unit = 1 part

X : Y = 6 units : 9 parts = 6 units : 9 units = 2 : 3

cheers.

Hi hi,

For your second equation, \"3/10 C is shaded, so 3 units + 3 parts = 3/10 C\", it doesn't look correct to me. Looks more like 3 parts = 3/10C. The 3 units is not part of circle Z.

I can't seem to get a logical answer. Can help reconfirm if there's anything wrong with this sum?

Thanks![/quote]Hi

Oops... I was in a rush and I forgot to add the \"modified\" diagram - I have swapped Y and Z in the original diagram.

With Y and Z as is, we will end up with an illogical relation between 1 unit and 1 part.

cheers.

[Andrew Lee]

Andrew Lee:

P6ians:

Hi

Q.1:
1h 30min--1.5h
1.5hx90=135km
135+25=160km
160km/(4-1.5)=64km/h
64x4h=256km(answer)
Q.2:(in this question,total remains the same)
Before. After
D:B. D:B
4:5.|9u 10:17|27u
12:15|27u
12u-10u=2u
2u----(100/2)
15u---$375(answer)

Sorry, for Q2, the question asking how many notes? not how much... :oops:

Hi MathizzFun, can you show me your \"modifed digram\"? tks